The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 18, 2000
Filed:
Dec. 19, 1997
Nobuo Kino, Kanagawa, JP;
Toshifumi Hibi, Kanagawa, JP;
Nissan Motor Co., Ltd., Kanagawa, JP;
Abstract
The invention relates to a power roller used for a toroidal-type continuously variable transmission. This power roller has on its first side a groove for receiving a bearing, and the surface of the groove (bearing surface) has a carbon concentration which is not lower than that of the back surface of a second side opposed to the first side. The power roller has a hardened outer layer having first and second portions which are respectively defined by the bearing surface and the back surface. The first portion of the hardened outer layer has an effective depth which is not shallower than that of the second portion thereof. The power roller is prepared by the sequential steps of surface-hardening, quenching, and grinding. The surface-hardening process is one of carburizing and carbonitriding. The grinding includes the sequential steps of: (1) grinding at least one of first and second outer portions a quenched preform of the power roller to remove the same, such that there is obtained a datum that is at least one of the surface of the groove and the inner flat surface which are respectively exposed by removing the first and second outer portions; and (2) grinding a third outer portion of the quenched preform, based on the datum, thereby to remove the third outer portion. The bearing surface of the power roller becomes high in carbon concentration, and the first portion of the hardened outer layer of the power roller becomes sufficiently deep in effective thickness.